Well,
because you feel at all, for one thing. And how, exactly,
you manage to do that has stumped philosophers and scientists
alike for centuries. The brain is the physiological final
frontier. Because the function of its parts can't be guessed
at by taking them apart, understanding how this enigmatic
organ becomes so much more than the sum of them has been
almost impossible.

With
the advent of fMRI, though, that's begun to change.

Short
for "functional magnetic resonance imaging,"
fMRI allows researchers to look at events instead
of just structures, and does so with a great degree of
precision. Color changes on fMRI scans show researchers
which part of the brain is active when a subject performs
a mental task such as speaking, listening to a bell ring,
or solving a math problem.

"It
adds function to structure," explains Dr. Joy Hirsch,
Director of the Laboratory of Functional MRI at the Memorial
Sloan-Kettering Cancer Center. "We've had a good
grasp of the basic structure of the brain for twenty years
or soCT scans and X rays have provided that view.
But fMRI noninvasively adds function: not just what it
looks like, but how it works."

"These
days it's pretty rare to identify new parts of the body,"
says Dr. Nancy Kanwisher, an MIT neuroscientist specializing
in fMRI. "But in the last few years people have discovered
dozens of pieces of the mind that no one knew about before.
And finding pieces of the mind is more of a rush
than finding pieces of the body ever could be."